In a 'Goku vs Beerus' fanfiction, it's really hard to say who would win. It could depend on how the author wants to write it. If the author wants to show Goku's growth, Goku might win through some new transformation or power - up. But Beerus is a powerful God of Destruction, so he also has a great chance of winning.
One possible fanfiction could involve Beerus being intrigued by a lemon - shaped object. Maybe it has some sort of strange energy that he senses. He could then take it on an adventure across the Dragon Ball universe, with humorous situations as he tries to figure out what this lemon - like thing is all about.
Goku's understanding of different universes and races could be deepened in fanfiction. Since Dragon Ball Super introduced the multiverse concept, fanfiction could explore how Goku interacts with and learns from beings from other universes, making him more worldly and less naive in some ways.
In this fanfiction scenario, it could be an extremely emotional encounter. Goku, who has grown so much in Dragon Ball Super, finally meeting his father Bardock. Maybe Bardock gets to see how his son has not only become a powerful Saiyan but also a protector of Earth. It could lead to some interesting exchanges about Saiyan heritage and the future of the Saiyan race.
Caulifla and Goku's relationship in fanfiction could be really interesting. Maybe in this fanfiction, they start as rivals. Caulifla, with her Saiyan pride, wants to prove she's stronger than Goku. But as they fight more, they begin to understand each other's fighting styles and develop a mutual respect. This could lead to some really cool training sessions where they both learn new techniques from one another.
There could be a storyline where Beerus, out of boredom, decides to train Goku Black instead of fighting him. But Goku Black misinterprets this as a sign of weakness and attacks Beerus. This could lead to a battle where Beerus has to hold back at first to avoid killing Goku Black, but as the fight progresses, he realizes he has to use his full power to subdue him.
One of the interesting power - ups could be his Ultra Instinct form. In fanfiction, it might be further enhanced, like having different levels that are not shown in the original. For example, he could have an Ultra Instinct - Kaioken combination which would be extremely powerful.
Dragon Ball Super vs GT in fanfiction can lead to some really interesting character developments. The different timelines and power systems in both series offer a lot of room for creativity. In some fanfictions, the younger characters from Super might meet their older counterparts from GT. This can create a contrast in personalities and fighting styles. For example, Trunks in Super is more used to the modern power-ups and technology, while Trunks in GT has a more 'old - school' approach. Fanfic authors often use these differences to create engaging stories that explore not only the battles between the two series but also the underlying themes and character growth.
One possible fanfiction idea could be that Goku's daughter has unique powers that are a combination of his Saiyan strength and something new, like the ability to control time on a small scale. She might struggle to fit in with the other Z - fighters at first because they see her as just Goku's daughter, but she proves herself by facing a new, powerful enemy that the others can't defeat easily.